wel it depends on if you want matching outfits or not
family type things
fred wilma and pebbles
homer marge and maggie
wendy michael and sorry can't remember the name of the little boy ( the darling children from peter pan)
peter pan wendy and tinkerbell
lady tramp and scamp

no matching
pirates
egyptians
nun
victorians
dr who
mad hatter
animals (such as cat or dog)
go in a onesie and have a pj party
dorothy from wizard of oz
zombies
aliens